1. Field of the Invention
This invention relates to magnetic tape recorder drive mechanisms, particularly to those adapted for use with reel-to-reel tape cassettes.
2. Description of the Prior Art
Cassette type recorders are perhaps the most common and accepted format of magnetic tape recorders, particularly in the consumer or inexpensive recorder portion of the market area. Because of the desire to provide cassette recorders which are both light weight and relatively inexpensive, numerous different mechanisms have been developed for effecting rapid motion of either the supply or takeup reels of the cassettes, to provide fast forward or reverse searching operations.
Typically, cassette decks have evolved into two general categories, those having a single drive motor, from which rotary motion is coupled to a tape drive capstan and to the supply and takeup reel spindles, and those having multiple drive motors in which a separate motor is used to drive the tape drive capstan and an additional motor (or motors) is used to drive the supply and takeup reel spindles.
Recorder decks falling in the latter category have heretofore either used completely separate motors for driving the supply and takeup spindles respectively, or have utilized sundry mechanisms by which rotary motion from a single motor is alternately coupled to drive each spindle in the desired direction and in which braking mechanisms to appropriately inhibit spindle rotation are separately included. For example, U.S. Pat. No. 3,495,789 (Gerfast) discloses a web transport mechanism including a single motor which is coupled through a helix to a disc mounted between matching wheels. Depending upon the direction of rotation of the motor and the helix, the disc is driven into contact with one or the other of the wheels. Each wheel is coupled to a respective one of the supply or takeup reel spindles to provide the appropriate driving force. When rotation of the helix is stopped, the inertia of the disc causes it to move along the helix from a drive position against one of the wheels to a braking position against the other of the two wheels (Column 2, lines 26-39). While the mechanism thus eliminates separate braking members, the construction is undesirably complex and fails to provide braking action to both spindles so as to minimize slack in tape exposed between the two reels.
Another type of cassette deck utilizing separate motors for driving the capstan and the reel spindles is depicted in U.S. Pat. No. 3,532,293 (Rose). In that patent, a drive hub 26 coupled to a motor drive mechanism (not shown) is caused to be shifted into contact with the periphery of either turntable on which the respective spindles are positioned. The specific means for effecting the requisite motion is not there disclosed, and a separate braking device is depicted for impeding rotation of the turntables.